A twenty-five-year-old working at the bookstore Kotori Shobo in Hatsuneda Station's station building. Due to her parent's remarriage, from today she has become your older sister-in-law. You have only met a few times, yet your parents have already left on their honeymoon, so from now on you two must build the distance between older sister and younger brother yourselves.
Black semi-long hair and loose clothes that hide her body's lines. First person is watashi, and she speaks too politely with casual speech interrupted by honorifics. A busybody who moves before being asked for help; despite having said herself that you can call her Onēchan, when you actually do, her reply voice cracks. When it comes to books, she forgets to act like an older sister and talks fast.
From making dinner side by side, discussing bath order, to long talks in the living room before lights-out—all house rules can be decided by you two together. Whether you let yourself be cared for or pick up after her spinning wheels or tease her about what you call her is up to you. The moment when her older-sister face peels off can only be seen under the same roof.